Special Notice #265: Bright Symbiotics in Sgr, Cyg, and Oph

Observer S. O'Connor reported late last week that the symbiotic stars V4018 Sgr, CH Cyg, and V2523 Oph all appeared to be in outburst or brighter than normal. He reports: V4018 Sgr at V=11.59 on JD 2455981.021 (2012 Feb 23.521); CH Cyg at V=7.30 on 2455982.976 (Feb 25.476); and V2523 Oph at V=11.67 on 2455981.0 (Feb 23.5). Other more recent visual observations of CH Cyg by G. Holmberg (vis=7.6 on 2455983.4993) and D. Barrett (vis=7.4 on 2455985.6013) confirm the star is well above magnitude 8.0 at this time. CH Cyg has been rising for several months, and may be reaching a maximum soon. All three stars are worthwhile targets for nightly observations. Both visual and instrumental observations are encouraged; instrumental observers are asked to use standard photometric filters (priority on V) and to calibrate and transform their data if at all possible.

U. Munari (INAF-Padova) et al report via Astronomers Telegram #3946 that V2523 Oph is in outburst and is expected to rise. They have also discovered that the current outburst episode has triggered a bipolar jet from the accreting star, and additional observations throughout the current outburst may be useful for interpreting this phenomenon.

Finally, we also note that we have received a request for observations of CH Cyg from Dr. Margarita Karovska in support of Chandra observations scheduled for the month of March 2012. We will be issuing an Alert Notice for this request soon, but observers are asked to add CH Cyg to their nightly observing plans at this time.

The (J2000) coordinates of these three symbiotics are as follows:

V4018 Sgr: RA: 18 25 26.84 , Decl: -28 35 57.5

CH Cyg: RA: 19 24 33.07 , Decl: +50 14 29.1

V2523 Oph: RA: 17 08 36.57 , Decl: -17 26 30.4

Please report observations of these three objects using the names above.

This AAVSO Special Notice was prepared by M. Templeton.

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